1. A CALL TO INNOVATION
During a single week in late 2008, Bhavesh Chauhan, a software engineer in Hyderabad, India, received four emails with missing attachments. Wanting to end such embarrassments, he used free time to code an Outlook extension that scanned emails for words indicating an attachment. If nothing was attached, an alert would pop up.

Chauhan: I thought this would be a good feature to have in Outlook, but since I didn't have a direct communication line with the Outlook team, and I was working in India, I decided to just create a personal add-on.

2. SETTING A SITE
In early 2009, Microsoft launched the Garage, an incubator for employee projects. A giant building on the Redmond, Washington, campus was filled with hardware fabrication tools, while free hosting and virtual machine access were offered to software developers.

Chauhan: I'd started on the idea but got to a point where I needed to add more features. The Garage seemed like a good platform for reaching experts.

3. THE DETECTOR EVOLVES
Chauhan's tool was such a hit among his Hyderabad officemates that he brought it into the Garage, remotely, to solicit feedback. There, colleagues helped him expand language compatibility and test before launch. In May 2009, Microsoft released a beta version through its download center with an add-on that tracked accuracy. It also polled users to see how they felt about a machine double-checking them.

Chauhan: I began working with other people in the Garage community who were able to contribute to the project. It was very exciting. I really didn't think I was going to get that much reach out of such a small utility.

4. OUTLOOK GETS BRIGHTER
In all, Chauhan got feedback from 44,000 customers, leading him to tweak the detector to scan for a range of verbs and nouns suggesting an attachment. The survey also revealed that people tolerate false alarms if they eventually lead to a save. When a preview of Office 2013—the first update of the franchise since 2010—was released last summer, the detector was included.

Chauhan: If you work on other large projects, you don't really get comments from users. But I was getting a lot of customer emails that gave me a new perspective. People said they would forget to fill in subject lines, so we added that warning.

5. ENGINEER ASCENDS, GARAGE GROWS
Today, the Garage generates about 50 new projects a month, many of which result in internal tools or improvements to existing products. Some inventions win patents, which come with a monetary bonus. Chauhan's wasn't unique enough for that—Gmail added a similar feature in 2010—but he benefitted in another way: The detector helped him land a software-development-engineering gig in Redmond.

Chauhan: I'm not working on any Garage projects right now, but in my current team, if I have certain kinds of requirements, I know which experts I can reach out to. That was part of the learning experience.

[Photo by José Mandojana]

[Ed. note: A quote by Bhavesh Chauhan about user comments on large projects has been clarified in this online version of the print article from the April issue of Fast Company magazine.]

A version of this article appeared in the April 2013 issue of Fast Company magazine.